WASHINGTON (Reuters) - The House Energy and Commerce Committee asked AT&T Inc (T.N), Verizon Communications Inc (VZ.N) and Qwest Communications International Inc (Q.N) on Tuesday to describe how U.S. government agencies sought to obtain information about customers' telephone and Internet use.

Last year, it was widely reported that some big telephone companies allowed the U.S. government access to millions of customers' telephone records for an anti-terrorism program. Qwest said it refused the government's request.

"If reports about the government surveillance program are accurate, Congress has a duty to inquire about whether such a program violates the Constitution, as well as consumer protection and privacy laws," said Rep. John Dingell, the Michigan Democrat who heads the powerful energy and commerce committee.

The committee also wants to "examine the difficult position of the phone companies who may have been asked by the government to violate the privacy of their customers without the assurance of liability protections," Dingell said in a statement.

Officials with AT&T, Verizon and Qwest were not immediately available for comment.

Letters sent to the phone companies asked them to describe how government requests for customer information are made and how the records are disclosed. The lawmakers also want to know if the government tried to install equipment on phone networks to intercept Internet traffic or presented a subpoena ordering the companies to install or permit such equipment.

The letters also asked phone companies if they provided information to the government about customers' "communities of interest" or networks contacts.

Dingell set an October 12 deadline for all three companies to respond to the committee's request.

Copies of the letters sent to the phone companies were posted on the committee's Web site at: http://energycommerce.house.gov/Press_110/110nr98.shtml.